1 use proc_macro2::TokenStream;
2 use quote::{quote, ToTokens};
3
fold_quote<F, I, T>(input: impl Iterator<Item = I>, f: F) -> TokenStream where F: Fn(I) -> T, T: ToTokens,4 pub fn fold_quote<F, I, T>(input: impl Iterator<Item = I>, f: F) -> TokenStream
5 where
6 F: Fn(I) -> T,
7 T: ToTokens,
8 {
9 input.fold(quote! {}, |acc, x| {
10 let y = f(x);
11 quote! { #acc #y }
12 })
13 }
14
is_unit(v: &syn::Variant) -> bool15 pub fn is_unit(v: &syn::Variant) -> bool {
16 match v.fields {
17 syn::Fields::Unit => true,
18 _ => false,
19 }
20 }
21
22 #[cfg(feature = "debug-with-rustfmt")]
23 /// Pretty-print the output of proc macro using rustfmt.
debug_with_rustfmt(input: &TokenStream)24 pub fn debug_with_rustfmt(input: &TokenStream) {
25 use std::env;
26 use std::ffi::OsStr;
27 use std::io::Write;
28 use std::process::{Command, Stdio};
29
30 let rustfmt_var = env::var_os("RUSTFMT");
31 let rustfmt = match &rustfmt_var {
32 Some(rustfmt) => rustfmt,
33 None => OsStr::new("rustfmt"),
34 };
35 let mut child = Command::new(rustfmt)
36 .stdin(Stdio::piped())
37 .stdout(Stdio::piped())
38 .spawn()
39 .expect("Failed to spawn rustfmt in stdio mode");
40 {
41 let stdin = child.stdin.as_mut().expect("Failed to get stdin");
42 stdin
43 .write_all(format!("{}", input).as_bytes())
44 .expect("Failed to write to stdin");
45 }
46 let rustfmt_output = child.wait_with_output().expect("rustfmt has failed");
47
48 eprintln!(
49 "{}",
50 String::from_utf8(rustfmt_output.stdout).expect("rustfmt returned non-UTF8 string")
51 );
52 }
53